THE TREATMENT OF METASTATIC THYROID CANCER WITH RADIOACTIVE IODINE: CREDITS AND DEBITS*†

Abstract

25 patients with metastatic thyroid cancer were studied and/or treated with I131. In 4 patients, unequivocal evidence of improvement has been obtained; tumor nodules regressed and there was histologic evidence of striking radiation damage in the tumor remnants. Tumors without iodine-collecting capacity, or those with too little collecting ability, can be influenced in the direction of greater function by one or more of 3 means: Total thyroidectomy, the admn. of thyrotrophic hormone, and prolonged admn. of large doses (up to 1.5 g. per day) of thiouracil. Following such procedures the collection of I131 may be increased many-fold. These findings suggest that not all thyroid cancer is completely autonomous. On the other hand, episodes of transient hyperthyroidism (corroborated by elevated serum precipitable iodine levels) were seen in 3 cases several days after therapy; amenorrhea developed in 3 women under the age of 41 following treatment; and hemato-poiesis was depressed, as shown by changes both in the bone marrow and in the peripheral blood. Such changes were seen in all patients treated, and were for the most part transient. However, one patient developed a fatal pancytopenia with death supervening 35 days after therapy.